De Sitter space

De Sitter space is what helps to define the shape of our universe. The universe is thought to be a "curved space" and De Sitter space is a particular type of curved space. This curved space is like a balloon--it looks curved because it is expanding, and as it expands, it gets wider and wider. The points on the balloon are like different parts of our universe. Everywhere we look, the universe looks the same, so this curved space helps to explain why.